The invention relates to a patient monitor and, particularly, a patient monitor for continuously monitoring one or more physiological signals of a patient and for determining a probability that a patient has acute cardiac ischemia based at least in part on one of the continuously monitored physiological signals.
Every day, patients arrive at an emergency room of a hospital complaining of chest pain. The chest pain may be a symptom indicating the patient is experiencing a myocardial infarction or, alternatively, the chest pain may be a symptom indicating the patient is experiencing a lesser medical condition (e.g., heartburn or indigestion). Statistics show that quickly identifying whether a patient is having a myocardial infarction may minimize the amount of damage to the heart. However, performing the necessary tests to correctly determine whether a patient is experiencing the myocardial infarction or heartburn are expensive.
One instrument used to predict whether a patient is likely experiencing a myocardial infarction is an electrocardiograph capable of calculating a probability that the patient has acute cardiac ischemia. If the patient has a high probability of acute cardiac ischemia, then the patient should be further tested to determine whether the patient is experiencing a heart attack. One instrument for determining a probability of a patient having acute cardiac ischemia is an Acute Cardiac Ischemiaxe2x80x94Time-Insensitive Predictive Instrument (ACI-TIPI). ACI-TIPI is described in detail in Selker et al., H. P. A Tool for Judging Coronary Care Unit Admission Appropriateness, Valid for both Real-Time and Retrospective Use: Medical Care, VOL. 29, No. 7 July 1991), pp. 610-627 and Selker et al., H. P. Erratum: Medical Care, Vol. 30, No. 2 (February 1992), p. 188, both of which are incorporated herein by reference.
The ACI-TIPI calculates a score representing the probability of a patient having acute cardiac ischemia. Based on the probability of the patient having acute cardiac ischemia, an experienced doctor or technician can determine whether the patient should be admitted to the coronary care unit. Once admitted to the coronary care unit, the patient can undergo more complicated, expensive and time consuming tests to determine whether the patient is experiencing a heart attack.
Prior medical equipment having the capability of calculating a probability of a patient having acute cardiac ischemia consisted exclusively of electrocardiographs having ACI-TIPI. An example electrocardiograph capable of determining a probability that a patient has acute cardiac ischemia is the MAC(trademark)5000, which is manufactured and sold by GE Medical Systems Information Technologies, Inc. Electrocardiographs are not used for continuous, constant or ongoing patient monitoring, i.e., they typically only take a small time sample (e.g., ten to twelve seconds) of a patient""s electrocardiograms (ECGs). A separate piece of medical equipment (i.e., a patient monitor) is attached to a patient for continuous, constant or ongoing monitoring of patient parameters. One such patient monitor is the DASH(copyright)2000 brand patient monitor, which is manufactured and sold by GE Medical Systems Information Technologies, Inc. Such patient monitoring devices however have not heretofore included the capability of determining the probability that a patient has acute cardiac ischemia.
When the patient enters the emergency room complaining of chest pains, multiple pieces of medical equipment (e.g., a patient monitor and an electrocardiograph) may be attached to the patient at any time. Attaching multiple pieces of equipment to the patient requires time for attachment, space for each piece of equipment, and coordination among the emergency room staff. In addition, the patient may be periodically moved throughout the emergency room or the hospital. Consequently, requiring an electrocardiograph to be temporarily attached to the patient requires use of extra time, space, personnel, and restricts transferability, which may affect the care provided to the patient. Therefore, it would be beneficial to have a patient monitor, and particularly a patient transport monitor, capable of determining a probability that a patient has acute cardiac ischemia.
Accordingly, the invention provides a patient monitor for determining a probability that a patient has acute cardiac ischemia. The patient monitor includes an input device connectable to a patient to continuously acquire electrocardiogram (ECG) signals from the patient, an instrumentation amplifier connected to the input terminal to combine the signals and to generate at least one ECG lead, and an analysis module. The analysis module is operable to continuously read the ECG lead, to analyze a portion of the ECG lead for a period of time, and to calculate a probability that the patient has acute cardiac ischemia based at least in part on the analyzed portion of the ECG lead.
The invention further provides a method of determining a probability that a patient has acute cardiac ischemia. The method includes the acts of providing a patient monitor having an input device connectable to a patient, acquiring electrocardiogram (ECG) signals from the patient, generating at least one ECG lead in response to acquiring the ECG signals, continuously monitoring the ECG lead, analyzing a portion of the ECG lead for a period of time, and calculating the probability that the patient has acute cardiac ischemia based at least in part on the analyzed portion of the ECG lead.
The invention further provides a software program for a patient monitor. The software program is capable of determining a probability that a patient has acute cardiac ischemia. The software program includes the acts of reading at least one electrocardiogram (ECG) lead acquired from the patient, continuously monitoring the ECG lead, analyzing a portion of the ECG lead for a period of time, and calculating the probability that the patient has acute cardiac ischemia based at least in part on the analyzed portion of the ECG lead.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.